1. Technical Field
The present invention relates in general to wireless communications devices and in particular to firmware upgrades in wireless communications devices.
2. Description of the Related Art
The Unstructured Supplementary Service Data (USSD) messaging structure has been utilized within Global System for Mobile Communications (GSM) as a messaging type for transmitting USSD requests and/or USSD notifications to GSM-enabled wireless devices and/or user equipment. USSD provides session-based communication for transmitting messages to wireless communications devices within a wireless communications network. For example, USSD is used to send text between a wireless communications device and an application program within the network, such as prepaid roaming or mobile chatting. USSD is similar to Short Messaging Service (SMS), but, unlike SMS, USSD transactions occur only during the session. With SMS, messages can be sent to a wireless communications device and stored for several days if the device is not activated or within range.
USSD functionality is not supported by current Code Division Multiple Access (CDMA) networks. As a result, Third Generation Partnership Project 2 (3GPP2) has initiated development of this functionality for CDMA networks. When the CDMA infrastructure becomes capable of supporting USSD functionality, USSD service can be deployed across and throughout the GSM and CDMA network coverage area. However, the legacy CDMA mobile devices do not support the USSD feature, and as such, these legacy mobile devices cannot recognize the type of data content that is provided within a USSD message. As a result, USSD requests received at the CDMA legacy device will result in a failure event, regardless of whether the USSD request originated from a USSD enabled device or server of the GSM network or from a USSD enabled CDMA device or server within the overlapping GSM-CDMA network. Given the large number of legacy CDMA mobile devices, the large number of failure events resulting from an inability of these legacy CDMA mobile devices to support the USSD feature presents a major challenge to wireless communications networks.